Thermal isolator for microwave components with waveguide flanges

A waveguide structure for guiding high frequency radio waves, the waveguide structure comprising:

• a first flange member having a first waveguide port;
• a second flange member having a second waveguide port;
• and
• a waveguide spacer that includes:
• a band-gap layer composed of a dielectric substrate and a plurality of electrically conductive contacts inserted into the dielectric substrate, the dielectric substrate has a waveguide hole connecting opposite sides of the dielectric substrate and the plurality of electrically conductive contacts are arranged around the waveguide hole to form a band-gap structure;
• a dielectric first outer layer for contacting the first flange member, and the dielectric first outer layer at least partially covers a first side of the band-gap layer;
• and
• an electrically conductive second outer layer for contacting the second flange member, the electrically conductive second outer layer at least partially covers a second side of the band-gap layer and is electrically connected to each electrically conductive contact of the plurality of electrically conductive contacts, and the waveguide spacer is arranged between the first flange member and the second flange member so that the waveguide hole, the first waveguide port and the second waveguide port form a waveguide channel for guiding the high frequency radio waves, the first flange member is in direct contact with the dielectric first outer layer of the waveguide spacer, and the second flange member is in direct contact with the electrically conductive second outer layer of the waveguide spacer.